Air-conditioning-apparatus outdoor units that are installed in buildings, commercial facilities, or the like these days have a heat exchanger that is disposed along a rear surface and side surfaces and a fan that is disposed on a top surface. By driving the fan, a negative pressure is formed inside, a flow of air is produced around the heat exchanger, and then heat exchange using the heat exchanger is performed.
The heat exchanger is formed such that heat-transfer tubes perpendicularly penetrate through fins. The heat-transfer tubes are, for example, circular pipes, and the fins radiate heat conducted from the circular pipes due to refrigerant moving through the circular pipes. The heat-transfer tubes may alternatively be, for example, flat pipes.
The above-described heat exchanger includes a plurality of heat exchangers that are stacked on top of one another, and, for example, an upper heat exchanger has a larger number of rows of heat-transfer tubes. Such an upper heat exchanger is hung by a separate member or provided with a support plate therebelow, thereby being securely supported so as not to fall down (see, for example, Patent Literature 1).
Furthermore, such a heat exchanger is provided with a bottom plate for supporting a bottom of a lower heat exchanger. Because the bottom plate collects dew condensation water produced by the heat exchanger, it causes freezing or corrosion.
To counter this situation, for example, in a conventional outdoor unit, a plurality of drain ports are provided in the bottom plate to discharge the dew condensation water produced by the heat exchanger from the drain ports (see, for example, Patent Literature 2).
Furthermore, for example, in a conventional outdoor unit, by configuring such that the bottom plate is sloped and is provided with drain holes on the downstream side of the slope, the dew condensation water produced by the heat exchanger is discharged from the drain holes through the use of the slope (see, for example, Patent Literature 3).
Furthermore, for example, in a conventional outdoor unit, by providing a plurality of louver-like cut-and-raised portions in the bottom plate, at a position corresponding to the heat exchanger, the strength of the bottom plate is maintained, while improving the efficiency of discharging the dew condensation water produced by the heat exchanger (for example, Patent Literature 4).
Furthermore, for example, in a conventional outdoor unit, by disposing a heat pipe at the lowest position of the heat exchanger, the dew condensation water produced by the heat exchanger is heated, whereby freezing of the dew condensation water is avoided (for example, see Patent Literature 5).